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How To Do Image Stacking

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I am a new Indi/Ekos user ... and trying to discover how to do image stacking with my Canon t7i DSLR. I have the camera basically working on an rPi 4 ... but I can't seem to figure out how to stack images.

Trying to configure an automated method so that I can get improved imaging in my close to city lights polluted sky with stacking.

Thanks!

Ken
3 years 3 weeks ago #68020

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Replied by Avocette on topic How To Do Image Stacking

The RPi4 is remarkably powerful device but when it’s capturing and guiding etc, it probably doesn’t have enough grunt to carry out live stacking. I personally do this using SharpCap Pro on my monitoring/controlling pc laptop, I send a bunch of files from the RPi to the laptop using VNC Viewer File Transfer, and then live stack them by directing SharpCap to the ‘Camera Folder’ where the images have been located. This works very well but requires a lot of manual intervention. For a more automatic process I have also used SyncThing on both machines so that as every image file arrives in the RPi4 folder, it is subsequently transmitted to the capture folder on the laptop. I don’t use this any longer because I now use two astroberrys simultaneously for two capturing rigs and hop between the two, monitoring and controlling from the one laptop. In such a situation SyncThing (or maybe just I) got rather confused between the two RPis, and so I removed it. It’s quite possible that I could set up SyncThing again in a fully controlled way with two RPis and one laptop but I’m not an expert.
2 years 11 months ago #69759

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When your camera is really close to the subject, depth of field will be very shallow. For example, if you are using a 100mm lens, at a distance of 50cm (nearly 10 inches from your subject) with an aperture as small as f/16, the area which is acceptably sharp is just 1.9 cm (about 3/4 of an inch). Reduce the distance to subject to only 25cm (less than 5 inches) and the depth of field reduces to only 0.36 cm (1/6th of an inch).

How to Photograph the Images Needed For Focus Stacking
The only way to conquer this issue in order to get a greater depth of acceptable sharpness in a final photograph is with computational photography. That means using software to blend together a number of photographs which have been taken with different points of focus. This computational process is called focus stacking.
2 years 11 months ago #69774

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Replied by Andrew on topic How To Do Image Stacking

So neither of those initial replies are what you are interested in. While transferring images to be stacked is fine, rather than live stacking, it is typically done once all the images have been taken along with what are known as calibration frames.
The other reply regarding focus stacking in an entirely different image processing technique that is not applicable to astrophotography. 

What you are looking for is software that aligns and combines images with an averaging algorithm. That also can apply calibration frames used to clean up noise and gradients. 
DeepSkyStacker and SIRIL are free. There are also more advanced programs such as Pixinsight and Astro Pixel Processor.
You will need to post-process your stacked images in a good photo editor such as Photoshop, or GIMP which is free. 

This is something you'll want to do on a desktop, not on a raspberry pi. 
2 years 11 months ago #69942

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